Evaluation of material constants and SAW properties in LaCa4O(BO3)3 single crystals

Lanthanum calcium oxoborate, LaCa₄O(BO₃)₃ (LaCOB), single crystals were grown by the Cz technique. The material constants and SAW properties of the LaCOB crystal were evaluated. The LaCOB crystal belongs to point group m. Since the measurement process of the material constants in point group m has not been reported, we established a new measurement process including vibration modes and crystal substrates in point group m based on that in point group 2, which has been already described (Mason (1946)). Using the new measurement process, all the material constants of the LaCOB crystal at 25°C were determined by the resonance-antiresonance method. Moreover, by characterization of the SAW and pseudo-SAW (PSAW) on the X-, Y- and Z-cut substrates, a maximum coupling factor (k² = 0.6%) was observed on the Z-cut crystal at the Y-axis propagation, and a relatively low temperature coefficient of delay (TCD) (48 ppm/K) was observed on the Y-cut crystal at the Z-axis propagation.